Just a couple of comments on solar power.
I see SRP and other power utilities claiming large areas of desert to install centralized solar energy generation facilities. There may be economic reasons where large scale installations are more efficient, but it seems to me that it makes more sense to utilize the “empty” space on house and business roofs. There are several benefits, but primarily that power is generated right where it is used and so transmission costs and losses are almost eliminated. Roofs will last a little longer too by reducing sun and rain exposure. And in the summer the sunlight and power that doesn’t hit the roof lowers the temperature in the attic a little, reducing the cooling bill. It may increase the heating bill a little in the winter, but in Arizona that’s an acceptable trade-off.
The negative of solar, wind and other alternative sources of power, however, is that it is not available 24 x 7 x 366. The power company may use less fuel when the alternative sources are active, but they still need to have enough capacity to provide ALL the power for times when there is no sun or wind. The big problem is energy storage — a way to efficiently store the extra energy created by the sun or wind and distribute it when it is needed. Current chemical batteries are just not up to the task. Several other ideas for energy storage are in the works, including compressed air, raising and lowering water levels, and heat storage using molten salt or other materials, but until the problem of energy storage can be solved, alternative energy sources will have a limited usage.
6 responses so far ↓
1 Mom // Mar 6, 2012 at 1:18 pm
Would it be feasible in an apartment situation such as where I’m living to have the roofs covered with solar panels? There are approximately 60 apartments in each three story building. They do everything possible here to reduce expenses, so as not to raise rent.
2 Richard // Mar 7, 2012 at 8:04 am
There are a lot of things going on in the alternative energy field. Individual roof top installations have some great benefits, as you mention, but they are not the only answer. I think it is going to take a combination of new technologies and conservation to meet the needs of the country. The wind farms in many areas of the West are impressive, and they generate 24 hours a day as long as the wind is blowing. Many people who boondock in the desert near Yuma have wind generators in addition to their solar charging systems. They work quite well since the wind blows a lot there.
3 Daryl // Mar 7, 2012 at 11:24 am
Mom, the payback on solar power right now is about 10 years, so I’m not sure FS would want to sink cash in the investment. However, there are ways to lease the equipment and have a net reduction in monthly payments that might be worth looking into.
4 Daryl // Mar 7, 2012 at 11:32 am
Richard,
I think we are on the same page.
Wind power still has the same problem as solar, in that it doesn’t generate all the time. If peak usage occurs during a lull, there has to be adequate capacity to cover that. The result is that even if there was enough solar and wind to net all the energy requirements for a community, they would still need enough conventional power generating equipment to provide peak power demand. They would save a lot of fuel and the equipment would sit idle much of the time, but it would still be a capital outlay requiring maintenance.
Only improved storage technology will allow full independence from conventional power sources.
For RVers, on the other hand, with their more limited requirements, wind and solar can provide all the power they need because they can use batteries to store it. Batteries become too expensive for a large house and especially so for a community.
5 Dale // Mar 9, 2012 at 5:08 pm
I dont understand why batteries won’t work for a house. The initial outlay should be in relation to the size of your grid as a solar grid relates to an RV’s storage. Arn’t batteries a small percentage of the initial outlay?
6 Richard // Mar 10, 2012 at 9:09 am
Batteries are not inexpensive if you buy enough of them to provide the kind of power that a normal house consumes. They work well in computer room UPS systems, but they are designed to last only half an hour or so, giving time for the generators to come online. Enough capacity to run a house overnight or when the sun does not shine during rainy days would take a huge battery bank.
Not only are they expensive, but they have a limited duty cycle life. I expect to have to replace my batteries every 5 to 7 years.
My batteries are lead acid — standard batteries. There are some better batteries on the market, but for the most part they do not last much longer or have more duty cycles. There is a tremendous amount of research going on to develop better batteries. It’s one of the things that is holding back electric cars.
I am following a couple guys who are testing LiFeMnPO4 (Lithium) batteries in their RV’s. They have some very good points, but they cost several times what lead acid batteries. They also require very specific charging profiles. If you do something wrong you can kill them in a hurry.